A. The patients with small cell lung cancer treated at the NCI-Navy Medical Oncology Branch and VA Oncology Branch who survived for two or more years free of cancer were at a 16-fold increased risk of developing a second primary non-small cell lung cancer compared to the general population. The risk of developing a second primary non-small cell lung cancer was 11-fold increased in the 43 patients who stopped smoking after developing small cell lung cancer compared to 32-fold in the 12 patients who continued to smoke. Cigarette smoking cessation after successful therapy is associated with a decrease in risk of developing a second smoking-related primary cancer. B. The information on staging investigations of 451 patients with previously untreated small cell lung cancer entered onto study at the NCI- Navy Medical Oncology Branch and Veterans Administration was collected. The cost of each staging procedure was estimated and an algorithm was constructed analyzing all permutations of a sequence of procedures required to stage disease in patients with small cell lung cancer. The least expensive sequence of procedures could potentially save $1,418.00 per patient compared to performing all staging procedures on all patients. The major factor in reducing costs was the concept of stopping the staging procedures after a site of distant metastatic disease was identified.